From patchwork Tue Sep 15 14:13:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 264001 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 936E7C43461 for ; Tue, 15 Sep 2020 14:30:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 554D023D3A for ; Tue, 15 Sep 2020 14:30:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600180247; bh=ZDpgKMqIR75TT9/pOhLpxSZfykDF5VhWsBXA3cBlMPo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=wPHYDFpFBNREhyROKP76wd/5JThSbXBRpPnJX/SVSC6qvYxgXJTo3aA5RrTQwVo8s D1FW6ru+sEXb5+kRbKP4PTAz26b9x3rXCi+CmoxJ9W+btBNqDnEY7IB2NKJ5P6u5bU +u6DJyeKaDncWdcdHoMSDT2D2TpL8/biG0Jk3SCM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727024AbgIOOaq (ORCPT ); Tue, 15 Sep 2020 10:30:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:42304 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726985AbgIOO3B (ORCPT ); Tue, 15 Sep 2020 10:29:01 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 54CA122242; Tue, 15 Sep 2020 14:21:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600179696; bh=ZDpgKMqIR75TT9/pOhLpxSZfykDF5VhWsBXA3cBlMPo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zZ65xjx3wadi8pqCUfwHf5OwK5/xPw+jqDPG4K9gLZojWf31SS2a8tzA27VzCjWjM 86rmKLbPZh8dQE3sjssI2+mHKsCPztjyynwLlIQZ6E1m02aQnx+HkmvdPDYa7drb+O qHL/PJzJEg4ZFvaGMTKXCf4uJfCYXGOizQAkCKbM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Akinobu Mita , Jonathan Cameron , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 5.4 082/132] iio:adc:max1118 Fix alignment of timestamp and data leak issues Date: Tue, 15 Sep 2020 16:13:04 +0200 Message-Id: <20200915140648.201586848@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140644.037604909@linuxfoundation.org> References: <20200915140644.037604909@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jonathan Cameron commit db8f06d97ec284dc018e2e4890d2e5035fde8630 upstream. One of a class of bugs pointed out by Lars in a recent review. iio_push_to_buffers_with_timestamp assumes the buffer used is aligned to the size of the timestamp (8 bytes). This is not guaranteed in this driver which uses an array of smaller elements on the stack. As Lars also noted this anti pattern can involve a leak of data to userspace and that indeed can happen here. We close both issues by moving to a suitable structure in the iio_priv() data. This data is allocated with kzalloc so no data can leak apart from previous readings. The explicit alignment of ts is necessary to ensure correct padding on architectures where s64 is only 4 bytes aligned such as x86_32. Fixes: a9e9c7153e96 ("iio: adc: add max1117/max1118/max1119 ADC driver") Reported-by: Lars-Peter Clausen Cc: Akinobu Mita Signed-off-by: Jonathan Cameron Reviewed-by: Andy Shevchenko Cc: Signed-off-by: Greg Kroah-Hartman --- drivers/iio/adc/max1118.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/drivers/iio/adc/max1118.c +++ b/drivers/iio/adc/max1118.c @@ -35,6 +35,11 @@ struct max1118 { struct spi_device *spi; struct mutex lock; struct regulator *reg; + /* Ensure natural alignment of buffer elements */ + struct { + u8 channels[2]; + s64 ts __aligned(8); + } scan; u8 data ____cacheline_aligned; }; @@ -159,7 +164,6 @@ static irqreturn_t max1118_trigger_handl struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct max1118 *adc = iio_priv(indio_dev); - u8 data[16] = { }; /* 2x 8-bit ADC data + padding + 8 bytes timestamp */ int scan_index; int i = 0; @@ -177,10 +181,10 @@ static irqreturn_t max1118_trigger_handl goto out; } - data[i] = ret; + adc->scan.channels[i] = ret; i++; } - iio_push_to_buffers_with_timestamp(indio_dev, data, + iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan, iio_get_time_ns(indio_dev)); out: mutex_unlock(&adc->lock);